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1
General Audio / Re: Good requantizers?
Last post by bennetng -
These kinds of discussion really blurred the line between lossy and lossless. For instance, int32 and float32 only have 25 bits of overlapping lossless values (+/-16777216) so both formats are "lossy" if you are converting back and forth and it is unfair to call either format "lossless".

Let's say, if 16-bit a-law/mu-law were being chosen as the CDDA data format in the 1980s, would we still call 16-bit LPCM "lossless"?

BTW, if I have something to complain about typical floating point formats, I would say they have too many wasted NaNs, and there is no flexibility to choose the amount of exponent vs fraction bits. If you define your own floating point types, then they are not accelerated by generic processors.

Integers are wasteful in another way as well, of course.
2
General Audio / Re: Good requantizers?
Last post by C.R.Helmrich -
There is also A-law and µ-law as another form of lossy compression with fixed bit-per-sample count, but as saratoga indicated, those don't sound better than DPCM since they are missing the prediction part (and are, therefore, less efficient).

Note that A-law and µ-law are similar in concept to a floating-point number representation. I just rediscovered this Float16 discussion which I remembered, and A/µ-law are a kind of "Float8" representation. But all of this represents lossy requantization, I don't think any requantization to a fixed lower bit-depth can, in general, be lossless.

Chris
5
General Audio / Re: Good requantizers?
Last post by saratoga -
So, to summarize - are there any other interesting ways to requantize 16 PCM bits to 8 PCM bits except simply discarding bits, rounding, or dithering with noise shaping?

No, or at least none that are better.  An 8 bit PCM signal has an SNR of < ~48dB.  You can use noise shaping to move noise to low frequencies or to high frequencies, but the SNR is still limited to 48 dB.  If you want to increase SNR,  you need more bits or to compress those bits.
9
Listening Tests / Re: Personal Blind Listening Test of the latest codecs at 40kbps, 48kHz
Last post by Kamedo2 -
@Kamedo2
Can You please comment on how new pair of headphones  has affected your listening tests as your previous  tests were done using Panasonic RP-HT560?   Was it easier, faster or overall experience is pretty the same?  Does K712 have more extended frequency range, lower distortion to your judgement etc?

Thank You.

The fist thing to notice is that K712 plays at noticeably smaller volume.
It covers the entire ear and more comfortable than the RP-HT560.
When it comes to discerning extended frequency range, not much different.
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